The present invention relates to an actuation assembly particularly for double-glazing units.
It is known that double-glazing units are currently particularly appreciated due to their functional characteristics of thermal insulation and soundproofing.
In particular, double-glazing units are door and window units of the type comprising a perimetric frame which supports two parallel panes which are at least partly transparent to light and form, between them, a sealed air space which accommodates light blocking means (Venetian blinds, pleated curtains or the like) moved by motor means from a fully packed or rolled-up condition to an unfolded condition which provides said blocking and vice versa.
One of the main problems of these double-glazing units is transmitting the motion of the motor means to the kinematic systems for moving the blocking means without compromising the hermetic seal of the frame of the double-glazing unit.
For this purpose, magnetic couplings have been conceived which are arranged partly inside the double-glazing unit and partly outside it and are substantially constituted by two facing shaft segments which support mushroom-shaped expansions constituted by circular permanent magnets.
In particular, the internal and external magnets face each other during use, so as to close axial lines of a magnetic field.
Automatically-actuated external magnets are associated with electric gearmotors and are accommodated with them in box-like structures which are applied to the double-glazing units in various manners.
Although the magnetic couplings solve the problem of hermetic sealing, they are not free from drawbacks.
First of all, it is known that the force transmitted by the magnetic couplings varies according to the facing surface, which is proportional to the closed field lines; accordingly, in this regard it is evident that in order to increase the force that can be transmitted by the coupling it is necessary to provide magnets having larger radial dimensions.
However, the seats for accommodating the magnets cannot easily withstand radial size increases, since they lie predominantly longitudinally.
An assembly has recently been devised which comprises a magnetic device for kinematic connection between an electric motor and the kinematic systems for moving the blocking means.
The assembly is composed of a ring of first permanent magnets, which is connected so as to rotate together with the actuation axis of the blocking means, and a ring of second permanent magnets having a pole orientation which is parallel and identical to that of the first ring; said second ring is adapted to turn in relation to the rotation of the first ring due to the closure of radial field lines.
The two rings can be coaxial, one inside the other, or parallel to each other.
In the first case, the motor is arranged between the panes but is encapsulated in a box-like structure which makes it removable and separate from the atmosphere inside the double-glazing unit.
Although this first case is a considerable improvement in terms of reducing space occupation, it does not allow controlled stepwise rotation of the motor and therefore it is difficult to provide fine adjustment of the orientation of the laminas if the blocking means is a Venetian blind.
This shortcoming is in any case also present in the magnetic couplings associated with motor drives described earlier.
In the second case, one of the two rings of magnets is internal and the other one is external, i.e., one of the panes is interposed between them, and the motor is coupled to the external one.
Also in this case, stepwise adjustment of rotation is not possible.